Tag: restful

I recently worked on updating an app I made a couple of years ago, that was using Yelp’s API. I was running into some issues deploying the older version of the app to Heroku, so I decided to update the API it was using to the latest version for Yelp, v3.

As I’m writing this, I found that the Yelp API documentation was a little confusing. The older API required a consumer key, consumer secret, token, and token secret. The Yelp Fusion API only requires an Authorization parameter.

Authentication for the Yelp API is outlined here, although I had to do a bit of fiddling around until I was able to successfully make an API GET request. Here’s what Postman looked like once I was able to make a successful call (click the image to see a larger view):

Something I wasn’t aware of from the APIs I’ve worked with, is that the Headers required a Content-Type with the value application/json and an Authorization with a value that started with the word Bearer, a space, and then the API key I had received from Yelp. So the value looked something like Bearer 203498lksjsdlkfej9if

An API is a set of routines or functions. It’s an interface used for performing tasks, retrieving data, and manipulating data. APIs use HTTP methods, which are used on a resource to GET, POST (submit form data), PUT (for updating files), PATCH (a partial update), and DELETE.

Adding an API

Bolt-on strategy – when you already have an application and are adding an API to it

Greenfield strategy – no underlining application. There’s complete freedom and flexibility to do what you want. Generally the “API first” or “mobile first” mentality.

Facade strategy – wraps existing logic with replace as you go. This is ideal for legacy systems so the application is always functional.

Designing the Relationship

Independent – the resources may exist regardless of the other existing but they may reference each other

Dependent – one resource cannot exist without the parent

Associative – they are independent of each other but the relationship contains additional properties to describe it

Planning the Relationships

Ask yourself the following questions:

Can both resources exist without the other?

Does one resource only exist when the other exists?

Does the relationship between resources require more information than just the links between them?

It should be relatively easy to map out the flow, action, etc for each resource. If not, you need to revise your design.

Consider using notecards to write down each resource action

REST

REST stands for Representational State Transfer

It’s an architecture for designing network-based applications

It is not a protocol, framework, or standard

Benefits of Stateless Servers

Visibility – monitoring systems and developers do not need to look beyond the request to trace a bug

Reliability – easy to recover from system failures

Drawbacks of Stateless Servers

Network Bandwidth – client sends state for every request

Complexity – all clients must handle their states

Benefits of Caching

Performance – for stateless and caching, many requests do not need to go all the way to the server

Scalability – server gets fewer requests so it can handle more clients

Drawbacks of Caching

Data reliability – clients might use stale data

Facets of a Uniform Interface

Self descriptive messages

Server includes metadata, such as Content-Type, to help clients process the responses

Hypermedia as the engine of application state (HATEOAS)

Client only assumes a fixed entry-point to the API, the server tells clients all other available actions through hyperlinksBenefits of a Layered System

Encapsulation (simplify an interface to a legacy server)

Scalability (layers enable load balancing)

Security (add access control rules to data crossing a boundary, just like a firewall)

Recently I did some document diving to find out more about different styles of software design. When it comes to building software, I’m someone who is more familiar with getting things to work, and I haven’t focused too much attention on discussing my approaches. So in an effort to become more eloquent about the way I describe my work, I thought I’d share an overview on software design styles and the cycle of software design:

Service-oriented architecture (SOA): a style of software design where services are provided with application components through a communication protocol over a network. The elements of SOA include:

Application frontend, service, service repository, service bus

Contract, implementation, interface

Business logic, data

A web service is an example of an SOA with a well-defined set of implementation choices.

Representational state transfer (RESTful): RESTful web services allow systems to access and manipulate web resources by using a predefined set of operations. RESTful includes the HTTP methods get, put, post, and delete. More information on what these mean include the following:

Get: retrieves a representation of the collection

Put: replaces the addressed item of a collection, or if it doesn’t exist, it creates it

Post: create a new entry in the collection

Delete: delete the item in a collection

Model-view-controller (MVC): a pattern for implementing user interfaces. It’s broken down into three components:

Model: directly manages the data and logic of the application

View: the output of the information, how the information is presented to the user

Controller: uses input from the user to make changes to the model or view